....Wife - She is small in height and weight. 5'4" and 120lbs. Using the old "up-to-the-chin" method... she would need a 139ish - However I cannot find such a size without going into youth boards which tend to be of lesser quality....

That is ABSOLUTELY the wrong method for determining board size!!!!! Forget that method, it's garbage!

Go to the board manufacturer's web site and check the weight/size range scale for the model(s) you/your wife are interested in! Same for your daughter! Although for her you may get away with sizing up a bit if she is still growing significantly year to year!!

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You're only Young Once,.. but you can be Immature FOREVER!